Aircraft: EMB ERJ 135 ER/LR
Phase of flight: Final Approach
Anomaly: ATC Issue All Types; Inflight Event / Encounter Weather / Turbulence

Air Carrier X was inbound to the ZZZ Airport. A severe thunderstorm was North of the ZZZ airport. Distance of the storm in relation to the airport was unreliable due to weather RADAR being out of service. We were able to see limited precipitation on the RADAR; however; we were unable to determine the intensity or if there was more weather that was not being displayed. A Convective Sigmet was valid for the Northern portion of ZZZ airspace. This information was included on the ATIS. We received a report from a Regional Jet that landed at the airport approximately 20 minutes before Air Carrier X entered our airspace and reported Moderate Turbulence on final for Runway 27; and Low Level Wind Shear Advisories were in effect. All the information was passed along to the crew inbound to the airport. I observed the wind at the airport at the time when Air Carrier X was inbound start to shift. Wind for most of the evening stayed approximately out of 200 and about 10KTS. The wind started to shift. Weather North of the airport started to intensify with lightning becoming more frequent and violent. When Air Carrier X checked onto my frequency he was cleared for the Visual Approach; had the airport in sight; I had visual on the aircraft; therefore I cleared him to land with a wind check. Visibility was still very good at the airport and to the South; North of the airport visibility started to drop with ceilings coming into effect. As he lined up on final the wind was still very strong for our airport out of the NE and I issued another wind check. Approximately on 1/2 mile final I observed the aircraft abruptly pull up and his left wing start to dip. Aircraft made a quick transmission that they were going around. My gut was telling me that he was doing a wind shear escape; however the pilot did not use that exact phraseology; which put me into a difficult position of not issuing to enough instructions to the aircraft; or saying too much while the pilot is trying to maintain control of the aircraft. Aircraft I've observed in past go around; nothing compared to the way Air Carrier X was turning and climbing. Our standard procedure is to issue runway heading and maintain 3;000 FT; however; due to the weather conditions and for the sake of safety; runway heading was the last place I wanted to put the aircraft. That would have been straight into the severe thunderstorm. I issued instructions to the aircraft to enter a left traffic pattern for Runway 31; which allowed the aircraft to continue his turn and get away from the thunderstorm at the pilots discretion. Once I observed the aircraft turning into a safe direction; I issued instructions to climb and maintain an altitude of 3;000 FT. He was climbing so fast I transferred control of the aircraft to my Approach Controller. The Approach Controller and I coordinated off line since we were right next to each other in the tower on Air Carrier X conditions and what was issued to him. We had no other aircraft in the air at the time and was able to put Air Carrier X wherever he wanted without any other conflicting aircraft. Approach then took him South away from the airport and it was approximately 20 miles before we were able to collect information from the pilot as to what his intentions were and the reason for the go around. From the report I received; the pilot described that was the worst flight conditions he has ever been in. It took full power to accelerate enough to climb out of the hazard; and he believed that they were in a Micro-burst. No LLWAS equipment showed any alarms during the time of Air Carrier X experiencing those conditions and going around. I did everything I could think of to inform Air Carrier X [crew] of the conditions of airport and keep him safe during his go around. [Need] proper working equipment. The weather RADAR was out on the one night that we actually have severe weather this whole summer! LLWAS equipment did not go off during the time when Air Carrier X experienced the hazardous conditions. Training for both controllers and pilots: 1. For controllers; a checklist to make sure all equipment and information is displayed properly and set properly for broadcast and detection. Have the checklists for specific weather conditions to ensure nothing is missed. 2. For pilots; proper training for pilots to use proper phraseology of their intentions during incidents. A go around and wind sheer escape maneuver are two different things and will tie the hands of the controller one way or the other. Having enough staffing to properly support an air traffic control facility. The combined experience between myself and the other controller was less than 1 year of CPC experience. Tower Controller described a go around event resulting from a probable microburst; the reporter noting a number of recommendations that might assist controller/pilots in future encounters.